1. Field of the Invention
The present invention relates to a ceiling fan adapted for use in factories and office buildings, the ceiling fan having flapping vanes.
2. Description of the Prior Art
There have been a variety of ceiling fans in use for industrial purposes at factories and office buildings. Typical examples are disclosed in Japanese Patent Applications Nos. 58-74246 and 58-179837. Each of the prior ceiling fans includes an elevating member slidably fitted around the motor shaft, stationary vanes fixed to the lower end of the motor shaft, flapping vanes pivotally connected to free ends of the respective stationary vanes, and wires each linking the free ends of the flapping vanes to the elevating member. The elevating member pulls up the free ends of the flapping vanes by means of the wires. This is repeated during the up and down movement of the elevating member, thereby enabling the vanes to flap continuously.
Under the known structure mentioned above the motor shaft must be long enough to allow the elevating member to move up and down over a required distance, and also to give space for providing the wires between the flapping vanes and the elevating member. This results in a large ceiling fan. A large ceiling fan is difficult to be installed in a limited space under the ceiling.